What to do with KEF B139s and T15s? A TL?

frugal-phile™
Joined 2001
Paid Member
a sealed box at .707

P7HD-sealed.png


Say 8.5 litres or so stuffed.

dave
 
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You are biamping. But if you have 2 (bipole) you might need to reorient them as they ideally will be pulled out from the corner, and work best if firing sideway
There's no real room in the corners for speakers - largely because there's a door in one of the corners. So they'll be pulled out well in front of the wood-burning stove. There's no hiding speakers in this fashion.
With a single i imagine that the B139 is front-firing… we had some issues with the single side firing driver in Tysen V1 and i tend to avoid that now.
Halving the cabinet means around 6" width or so for a baffle - I'm sure the 139s are wider than that meaning that one would stay on the 'side wall' (which is now at the front. So the wedge would have to be turned sideways changing the room decor so that would need approval.

I don't have these problems in my listening room :)
 
diyAudio Member
Joined 2007
It's not hard to make a sealed box too small but harder to make one too big. Vifa P-13 can work in a half litre as a midrange but I put mine in 5 to 8 litre boxes. I doubt may would hear the difference between an 8 litre box and a 10 litre box and I'm of the opinion that all small sealed boxes should be stuffed.
Mind you I've never heard any of the Mark Audio drivers so my opinion means little.
 
B139 bass is definitely a great loudspeaker I would like to own and hear one day.

The B110 and T27 or T15 are good drivers, too.

With my Pioneer fullrange drivers Pioneer TS-1310f and a cfa amp and some slight EQ I get true high end loudspeakers using polypropylene cones. Bextrene has some good acoustic properties in the same direction.

However I like stiff Polystyrol cones and it's a pity that today nobody uses this material for cones any more.

Dreaming of fullrange drivers with thin Polystyrol cones covered in sandwich aluminum foil.

Kef began to use in their first speakers alu foam alu sandwich.


https://www.whathifi.com/features/a-history-of-kef-speakers-from-the-k1-to-the-concept-blades
 

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BTW, I think the KEF Concord was the B139 & T15 speaker with the "phasing plate" in front of the bass unit. A large sealed box. It came about just after Laurie Fincham joined KEF from Celestion where he had done the Ditton 15. The "phasing plate" was a larger version of the plate in front of the Celestion HF1300, one of the most famous treble units of all time.
 
There is a pair of Concord's on UK ebay for £250 Buy it Now +£30 shipping.

Also, there is a second pair for £300.

1969 vintage so my concern would be the integrity of the rubber suspension but could be a 'cheap' way to get hold of the drivers.

https://www.ebay.co.uk/itm/196204629728

There is also a pair of Concertos which have all three drivers.

https://www.ebay.co.uk/itm/176224893409
 
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Lucky sod ;-) Why do people throw things away? I had a perfectly good Mullard 5/10 amp that my dad threw away after I left home - on the grounds of 'you didn't want that old mono thing!'


...and I think the 60s. There was a lot of ex-military surplus stuff around - oscilloscopes, radios, components etc that the tweed jacketers were constantly playing around with because it was dead cheap.
I spent many happy hours when a student in the surplus shops on Edgeware & Tottenham Court roads, having took the train from West Yorkshire.

On one occasion I hauled a very large valve oscilloscope back to my digs, which raised a few eyebrows on the train. I was chuffed when I managed to fix it - just couple of new valves.
 
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BTW, I think the KEF Concord was the B139 & T15 speaker with the "phasing plate" in front of the bass unit

It was - a much larger cabinet than the Celeste but the same drivers - and of course the plate. Radford also used the B139 in various designs - one very like the Concord (similar size) but using the HF1300 tweeter instead of the T15. The B139 had a similar plate fitted as KEF used.
 
I spent many happy hours when a student in the surplus shops on Edgeware & Tottenham Court roads
I got my first speakers from such a place in the Tottenham court rd when I was a student - RAM 150s - with a Dalesford woofer, ABR and an Audax tweeter. Nice speakers but not suitable for student/young people use - parties tended to blow the tweeters. Eventually I abandoned them - a piece of real stupidity. Don't see RAM speakers around any more - seen only one on ebay a few years ago.
 
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It was - a much larger cabinet than the Celeste but the same drivers - and of course the plate. Radford also used the B139 in various designs - one very like the Concord (similar size) but using the HF1300 tweeter instead of the T15. The B139 had a similar plate fitted as KEF used.
The phasing plate looks like the baffle opening not matching the 139's shape but having two semicircular cut outs. You can see it clearly in the ebay listing link that I posted.

I bulit my first speakers when I was about 15 but can't remember whch drivers I used. I think the cabinet was made from old veneered wardrobe doors - it had two so there was enough for the sides as well.
Of course there were very few speaker design books about in those days, especially not in a village or school library so there was no 'design' involved, just screw and glue together a sealed box, filled with loft insulation 'borrowed' when parents were at work.....

Ah, those were the days! Now everyone is frightened to go public about their own builds in case they get mocked by forumites.
 
I bulit my first speakers when I was about 15 but can't remember whch drivers I used. I think the cabinet was made from old veneered wardrobe doors - it had two so there was enough for the sides as well.
I was about that age as well when I built some reflex speakers from chipboard. The design came from Gilbert Briggs books and the drivers were 'music while you work' speakers from an old factory. I changed Briggs measurements without knowing why and the result was awful. Eventually they became the sound system in a Mk1 transit minibus and survived several years of potholers before some pissed-up Yugoslav put a boot through one of them after a very drunken party in the mountains of Montenegro. Last I knew of them was one survived a good 15 years as the speaker for a tiny bar right up in the mountains. The bar owner (Branko) apparently boasted that the speaker was designed, built and given to him by his English friends. I doubt the sound quality did much to convince the very few tourists that made their way to Brankos place that Britain knew how to do hifi!
 
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